Question

Margy is trying to improve her cardio endurance by performing an exercise in which she alternates walking and running 100.0 m each. If Margy is walking at 1.4 m/s and accelerates at 0.20 m/s2 during one of the running portions, what is her final velocity at the end of the 100.0 m? Round your answer to the nearest tenth.

Answer 1

The more simplistic answer is: 6.5 m/s

Answer 2

This is an example of a straight-line motion problem. To find the final velocity, the following formulas are used:

s = Vo*t + (1/2)*a*t^2
Vf = Vo + at

Where:

Vf = final velocity = ?
Vo = initial velocity = 1.4 m/s
a = acceleration = 0.20 m/s^2
s = displacement = 100m

Substituting to the first equation:

100 = 1.4t + (1/2)*0.2*t^2
t = 25.388s

Substituting to the second equation:

Vf = 1.4 + 0.2(25.388)
Vf = 6.5 m/s

Therefore, her final velocity at the end of the 100m is 6.5 m/s.